Printed circuit boards and other electronic components often employ multiple-pin heatsinks to dissipate the heat that they generate. Typically such heatsinks include a base plate which is mounted to the circuit board and has a plurality of attached pins extending from its upper surface. The plate and pins are composed of a heat-dissipating metal alloy.
Conventional brazing, welding and casting techniques for manufacturing such multiple-pin heatsinks exhibit a number of disadvantages. For example, in one brazing method the pins are received through corresponding holes in a narrow jig or die so that the upper ends of the pins extend above and the lower ends extend below the die. A layer of brazing compound is then disposed between the upper ends of the pins and the base plate. The compound is heated to braze together the pins and base plate and finally the die is removed. This is a time consuming, tedious and relatively expensive procedure. Brazing compound must be purchased and properly applied; the pins must be held in place; and heat must be properly applied. Moreover, it is often quite difficult to maintain all of the pins perfectly parallel to one another. And if even one pin is mounted in a crooked manner the die becomes very difficult to remove.
Casting methods require expensive molds and heat sources. Furthermore, the metal alloys employed in the casting of multiple-pin heatsinks are typically limited to materials which are relatively poor conductors of heat. This problem is exacerbated by the casting process because porosity and granular structure are typically formed in the cast pins and base, thereby further reducing heat dissipation. And due to the surface tension of the molten pin material, it is extremely difficult to draw that material into the extremely narrow pin molds, even using a vacuum pump.
Welding techniques are likewise expensive, time consuming and complex and often provide less than optimum results.